A reverse conducting insulated gate bipolar transistor (RC-IGBT) is a semiconductor device used for power conversion and the like. The RC-IGBT includes an IGBT and a diode which are connected in reverse parallel. In the RC-IGBT, a voltage oscillation may occur when the diode is switched. The voltage oscillation may causes malfunctions in other circuit elements connected to the RC-IGBT. For this reason, it is desirable that the voltage oscillation be small.